I have very different taste so while I don't agree on all of it I'll try to explain it for your point of view. I never was a fan of Disney's so called Silver Age and I would rank them from a 4 to a 6.
THe first three are very indebted to Disney in style but are fairly good films at least from an animation perspective. The films after Prince of Egypt never made enough money so Dreamworks stopped making them.
The three in the middle were either based on preexisting material like Shrek which was based on a book, Antz which was based off of a project underway at Pixar, or like Chicken Run were mainly Aardman films with Dreamworks' resources.
I agree on three of the last four being bad except Trolls which was in my mind, a fun piece of fluff but only a 7 out of 10 at most. And I think that the sequel, World Tour, was worse. It's clear that they were going for low comedy, even with Trolls which I enjoyed.
I imagine that some of the shift was due to the break of Dreamworks Animation from Dreamworks SKG and later the closing of one of the Dreamworks branches which was originally Pacific Data Images.
They thought audiences wanted CGI comedies instead of animated films that were a bit more ambitious with their storytelling or just even their animation. I think Katzenberg called traditional animation dead after Sinbad flopped.